The present disclosure herein relates to a method of manufacturing an organic light emitting device, and more particularly, to a method of manufacturing an organic light emitting device including a light extraction layer.
An organic light emitting device refers to a device in which a hole provided from an anode electrode and an electron provided from a cathode electrode are coupled in an organic light emitting layer formed between the both electrodes to form an exciton. The exciton is radiatively-recombined to emit light. Since the organic light emitting device is generally fabricated by physically laminating various components such as a substrate, an organic layer, and a thin film electrode, interfaces between layers may have different reflective indexes, respectively. When light emitted from the interface of each of the layers has an incident angle that is greater than a critical angle, the light may not be released to the outside and isolated therein. Eventually, only about 20% of the generated light is released to the outside, and most of the light is dissipated due to a wave-guiding effect caused by a difference between reflective indexes of a glass substrate, a transparent electrode, and an organic layer and a total reflection effect caused by a difference between reflective indexes of the glass substrate and the air.
In general, the organic light emitting device has a bottom emission structure in which a transparent substrate such as glass and a transparent electrode are applied as a lower electrode. However, in case of the bottom emission structure, since an opening ratio decreases due to an area occupied by a driving thin film transistor (TFT), a substantial emission area per unit pixel decreases as luminance decreases and resolution increases. Accordingly, a driving voltage increases to realize the same level of luminance, thereby reducing a reliability of the device and increasing a consumption of electric power. Thus, as a resolution of a display device has increased in recent years, demand for a top emission structure using a transparent upper electrode is increasing.